The present invention relates to a device for suspending a cab on a work vehicle and, more particularly, to a cab suspension device that is also capable of transferring loads from the rollover protection systems (ROPS) to the vehicle chassis when required.
Construction and agricultural machinery places considerable demands on the operator's cab suspension construction. In order to make the working environment of the driver comfortable, the suspension must be capable of reducing/eliminating the relatively powerful vibrations and shocks which are otherwise transmitted from the vehicle frame to the cab. Moreover, for reasons of safety, the suspension must be sufficiently strong to retain the cab on the frame even if the vehicle should overturn. Typical lighter duty agricultural tractor cab suspensions are designed with pivot connections at the front of the cab and vertical sprung connections at the rear of the cab. This arrangement has been found to be insufficient for heavier duty 4WD agricultural tractors which require moveable connections at the four corners of the cab mounting structure to provide adequate operator comfort. The movable connections must allow the cab to move freely without making hard contact during normal operation.
Agricultural tractors are also required to provide roll over protection systems (ROPS) to protect the operator in the event of a vehicle roll over. A suspended cab with ROPS typically includes a bolted connection with a resilient isolation mount connecting the cab to the frame. Cab movement is limited through this type of connector, but it provides the load capability necessary for the ROPS. As this attachment is relatively rigid, adequate operator ride comfort may not be provided on heavy duty tractors.
It would, therefore, be a great advantage to provide an improved mounting device for supporting a cab on an agricultural tractor frame that allows adequate movement for operator comfort while providing a sufficiently strong connection for transferring the ROPS loads to the frame. Further advantages would be realized by a mounting device that is sufficiently compact to be installed in a similar space occupied by a conventional spring mounting device. Still further advantages result from an improved cab suspension device that allows vertical, lateral and angular movement while still providing a suitably strong load transfer path for the ROPS loads when required.